How To Find The Source Of A Water Leak In Your Front Yard

So, there’s a really wet spot or large pool of water in your front yard, and you suspect a water leak. But where is it?

The 2 most common places are:

  • In the main service line between your water meter and home shutoff valve
  • In your irrigation system

We’re going to show you how to isolate these 2 parts of your plumbing system and use your water meter to find out where the leak is.

Note: Shut-off valves can break when you turn them on or off if they’re old or corroded.

How to check if the leak is in the service line

Water comes into your home from the city’s water main, through your water meter and then travels underground through the main service line to your home’s shutoff valve.

A diagram of how water gets into your home. Image source: Smart Home Water Guide

To see if this is where the leak is, we’re going to turn off the water to every other part of your home. To do this…

1. Turn off the water at your home’s shut-off valve

Look for the place where your service line comes out of the ground and goes into your home. This is most often in the front or corner of your home. However, in some homes in Atlanta, the shutoff is actually in the basement.

A shutoff valve. Image source: Smart Home Water Guide

To turn off the water, close the shut-off valve. This will likely be a gate valve like the one in the image below.

Closed shutoff valve. Image source: Smart Home Water Guide

2. Locate your water meter

Look for a metal lid on a concrete box near the curb. Use a screwdriver to lift the lid.

Water meter box. Image source: Smart Home Water Guide

3. Read the meter for a leak

You’re checking to see if water is still running through the meter. If it is, the leak is in your service line. If no water is going through the meter, the leak is somewhere else.

How you read the meter depends on the type of meter you have: analog or digital.

How to read an analog water meter: Look at the main dial hand and the low-flow indicator (usually a triangle or star that spins). If either of these are moving, there is water moving through the meter and the leak is in your service line.

Analog water meter. Image source: Smart Home Water Guide

How to read a digital water meter: You want to observe the flow rate. (All digital meters are different, so check with your city on how to read yours.) If the flow rate is zero, there’s no water flowing through the meter and the leak is not in the service line.

Digital water meter. Image source: Smart Home Water Guide

Most common locations for service line leaks

If you’ve isolated the leak to your service line, you now may be wondering where in the service line the leak is. Well, the most common places leaks occur in the service line are:

  • Near the shutoff valve. The copper pipe from your shutoff valve goes into the ground and becomes a PVC pipe. This junction or fitting can crack and leak.

Copper to PVC connection on water main. Photo source: BigAsLife

  • At fittings. Water leaks in your home’s main service line almost always occur at a fitting (or joint) in the pipe. So, if the service line has to turn and go under a driveway, for example, that’s a good place to check.

How to check if the leak is in your irrigation system

If you’ve gone through the above steps and the leak is not in your service line, the next most likely culprit is in your irrigation system. Here’s how to see if the irrigation system is the problem.

1. Turn your house shut-off valve back on

You want water to flow into your irrigation system. To do that, turn the house shut-off valve back on.

A shutoff valve. The pipe on the far left is flowing into the ground to your irrigation system. Image source: Smart Home Water Guide

2. Make sure all water-using appliances and faucets in your home are off

Every faucet and appliance should be turned off for this test. You want to make sure that nothing in your home could be using water.

3. Check the water meter

Use the same instructions as above to check the water meter. Your water meter should now be recording water use again.

To see if the leak is in the irrigation system, turn the water off to your irrigation system. In most homes this will be the valve after your backflow preventer.

Now, if the water meter stops recording water use, it means you’ve isolated your water leak to the irrigation system.

Most common locations for irrigation system leaks

Leaks in the irrigation lines that cause large wet areas in your front yard usually occur in one of 2 places:

  • In the pipe between the backflow preventer and an irrigation valve box
  • A malfunctioning valve inside an irrigation valve box

Get a professional plumber to fix your leak

Now that you know where the leak is in your yard, you can call a plumber to fix it for you.

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